In the shipping; industry a standard corner fitting has been established for shipping containers. Such corner fittings on the bottom of the containers will provide locations at which the container may be engaged by appropriate apparatus to secure the container on a transportation vehicle, e.g., truck, railroad car or ship. Such corner fittings on the tops of the containers are employed, for example, as a location to engage the container by an overhead crane for moving the container from one such vehicle to another, or for securing two vertically stacked containers together. A typical form of the apparatus used to engage the corner fitting comprises a shank axially and rotatably movable in the frame of the locking apparatus. At one end the shank has a crosshead proportioned to enter the oblong hole in the corner fitting when in one azimuthal orientation and rotatable ninety degrees to an orientation at which the crosshead is transverse that oblong opening whereby the corner fitting is then locked to the apparatus frame. The prior art has proposed and utilized various types of devices for axially and rotationally moving the shank and for locking the shank against those movements when the crosshead is positioned transverse the oblong opening in the container corner fitting. The present invention is primarily directed to a novel form of such device for controlling the rotational and axial positions of the shank of a locking apparatus.
Several standard forms of such locking mechanisms presently in use operate on the principle of a cam or a toggle joint. Thus they provide for axial positioning of the shank within a relatively limited range when the crosshead is being locked into the corner fitting. This is adequate so long as conditions are at the optimum for which the locking apparatus was designed. In actual use, however, the conditions are often not at the designed optimum resulting in difficulty in utilizing the locking apparatus embodying such operating mechanisms. For example, the bed of a trailer or a flatcar having such locking apparatus will become warped between the locations of the individual locking units so that the spaced units are no longer in a common plane. This can require an additional axial movement of the shank of one locking unit to adequately penetrate the respective corner fitting. Another common occurrence will be that the bed will have a high spot between the spaced units which high spot holds the container at an elevation above the plane of the units thereby requiring additional axial movement of the shank of at least one of the units in order to adequately penetrate the respective corner fitting. The container may become twisted so that one (or more) of the four corner fittings at the bottom of the container no longer lies in the plane of the other three.
The principal object of the present invention is to provide a locking mechanism wherein the shank of the locking device is effective within a greater range of axial movement than is the case with such devices commonly in use today. At the same time, the container may be securely engaged and held by the crosshead at any loction within the range of the axial movement of the shank. When the container is so engaged by the crosshead, the operating mechanism can be securely locked against accidental displacement which might result in a loosening of the engagement of the apparatus with the container corner fitting.
The operating mechanism is complete in itself; that is, no separate tools or the like are employed and thus the possibility of not having the tools available or their becoming lost is avoided.
The present invention also embodies a feature permitting the shank and crosshead of the locking device to be shifted in a plane transverse to the axis of the shank to thereby accommodate misalignments that may be present due to damage of the container or of the vehicle which is to receive the container.
In the present invention there is an annular rack adjacent the distal end of the shank of the locking device. This rack is engaged by a manually rotatable gear segment to move the shank axially. It is also engageable by the teeth of a locking member to prevent axial movement of the shank when the crosshead is in the locked position in the container corner fitting. Gears on the locking member and on the shank cause the two to rotate in unison and to permit the locking member to be used to rotate the crosshead to the position at which it is aligned with the opening in the container corner fitting, the initial part of that movement of the locking member resulting in an unlocking of the axial position of the shank.
Further objects and advantages will become apparent from the following description taken in conjunction with the drawing.